What does "Assets per month" in HereMaps pricing mean?

The pricing page https://developer.here.com/pricing#plan-details for HereMaps contains the term "Assets per month" for the freemium plan. I could not find any hint what this means?

Could someone explain me what an asset is for Heremaps and when do I use them?

An Asset is a person (including an end user), animal, device, cargo, means of transportation, vehicle or any other object which is

1. Located, tracked or displayed on a map, or
2. Provided route calculations or orders of destinations and/or routes, or
3. Has analytics derived by using the HERE Materials in a customer application or service for business purposes.

For example, HERE services are often used to help logistics providers manage vehicles in a fleet or a field workforce. If you manage 250 or fewer Assets, the Freemium and Pro plans will support your app. Contact us to license applications that manage more than 250 Assets.